261960640 has 56 divisors (see below), whose sum is σ = 625175280. Its totient is φ = 104552448.

The previous prime is 261960617. The next prime is 261960641. The reversal of 261960640 is 46069162.

It is a junction number, because it is equal to n+sod(n) for n = 261960596 and 261960605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261960641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274404 + ... + 275356.

Almost surely, 2^261960640 is an apocalyptic number.

261960640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261960640 is an abundant number, since it is smaller than the sum of its proper divisors (363214640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261960640 is an equidigital number, since it uses as much as digits as its factorization.

261960640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829 (or 1819 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 261960640 is about 16185.1981761114. The cubic root of 261960640 is about 639.8507464455.

The spelling of 261960640 in words is "two hundred sixty-one million, nine hundred sixty thousand, six hundred forty".